Electric level-indicator.



G. E. HENDERSON.

ELECTRIC LEVEL |ND|CATOR. APPLICATION FILED SEPT. 26; 1912.

l 1 5530 Patented Sept. 7, 1915;

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M l l L G. E. HENDERSON.

ELECTRIC LEVEL INDICATOR.

APPLICATION FILED SEPT. 26, 1912.

12,730. Patented Sept. 7, 1915.

2 SHEETSSHEET 2.

WITNESSES 0 ATTORNEY GEORGE E. HENDERSON, OF NEAR MANTON, CALIFORNIA.

ELECTRIC LEVEL-INDICATOR.

Application filed September 26, 1912.

To all whom it may concern:

Be it known that I, GEORGE E. HENDER- SON, a subject of the King of Great Britain, residing near Manton. in the county of Shasta and State of California, have invented certain new and useful Improvements in Electric Level-Indicators, of which the following is a specification.

This invention relates to means for electrically indicating at a distant point the height of level of water in a reservoir or ditch, or the pressure of steam or other fluid or other similar conditions.

()ne of the objects of the invention is to provide an electrical indicating device which will be substantially independent of changes of the pressure of the electric current used.

A further object of the invention is to provide such a device that will be more ac curate and certain in its action than is the case with other instruments heretofore used for similar purposes.

A further object of the invention is to provide such a device Which, when used with alternating current, avoids the necessity of employing variable contacts in the circuit of the line and the indications of which are affected by such changes in electric frequency and pressure as now occur in actual practice.

In the accompanying drawings: Figure 1 is a diagrammatic view of my invention as used with alternating current, and applied to means for indicating the level of waterin a distant reservoir or ditch. Fig. 2 is a detail view showing a modified arrangement of coils. Fig. 3 is a similar View showing another modification thereof. Fig. 4 is a similar view, showing in modification a portion of the device for use with direct or alternating current. Fig. 5 discloses a modified arrangement of coils and solenoids, for use withalternating current. Fig; 6 discloses a modified arrangement of resistances and solenoids, similar to that disclosed by Fig. 5, for-use with either direct or alternating current.

Referring to the drawing, 1 indicates a reservoir or ditch containing water of varia ble height. Pivotally secured to a suitable stationary support is an arm 2 carrying at its free end a float 3 acted upon by the water in the reservoir or ditch 1, and to said arm is pivoted, as shown at 4, one end of a rod 5 the other end of which is connected with a Specification of Letters Patent.

Patented s t I 7 Serial No. 722,485. "-1

- laminated soft iron core 6 of a fixed solenoid 7. By this means said iron core (3 is caused to move into the solenoid 7, the height of level of the water in the reservoir or ditch and the part, within the solenoid, of the iron core having corresponding values, the structure forming a variable reactance coil. Solenoid 7 of the variable reactance coil is connected by wires 8 and 9 to the station or point at which it is desired to know the height of level of the water in the reservoir or ditch 1.

At this station or point a wire 27 is divided into two branches 10, 11, connected respectively to fixed inner and outer co-axial solenoids or coils lying in the same plane. The outer solenoid 13, one terminal of which connectswith branch wire 11, is connected at its other terminal by a wire 26, to one terminal, of a reactance coil 18, the other terminal of which reactance coil is connected to a wire 8 which is connected through the solenoid 7 and 9 to the'wire 9. The inner solenoid 12, one terminal of which is connected to wire 10, is connected at its other terminal, by a wire 20, to. one terminal of a solenoid 21, the plane of which is at right angles to the plane of solenoids 12, 13, and. the center of which coincides with the center of solenoids 12, 13. The other terminal of solenoid 21 is connected by a wire 22, to one to wire 9. Wire 9 at its intersection with' the terminal of reactance coil 25, is connected by wire 9 to a source of alternating current, and wire 27 is connectedto the other terminal of this source.

A shaft 1 1 is pivotally supported at each end and free to rotate in the intersection of the plane of solenoids 12, 13 with the plane of solenoid 21. A laminated, soft iron plate forming an armature 15 is mounted on said shaft within the solenoids 12, 13 and 21, and is free to rotate within the solenoids 12 and 13. A pointer 16 moving over a fixed scale 17 which is outside. of solenoids 12, 13 and 21, is rigidly attached to the shaft 14.

The electric circuits of solenoids 12 and 13, considered from their respective starting points at wires 10, ll, encircle their common Each of the 4 indication due to variations of time of alternations of the operating current will be a' minimum for any desired height of level' of water in the reservoir or ditch 1, or that the sum of the errors of indication, due to this cause throughout the whole range of the indicator or throughout any part of it, may be a minimum. The greater the ratio of the impedance of each of the branch circuits, of which wire 10 forms a part of the one, and wire 11 a part of the other, to its ohmic resistance, and the less the difference between these two ratios, th'e less is the error of indications, due to variations of time of alternations of the operating current. The magnetic circuit of each of the reactance coils 18 and 25, consists of laminated iron or steel of high magnetic susceptibility in series with a suitably arranged air gap or space occupied by material of low magnetic conductivity and retentiveness. In this way the inductance of each of these reactancecoils is made to be practically constant for such values of currents through them as are likely to occur. I

It will be seen that the current flowing through the solenoid 12 and through solenoid 21 at right angles thereto is not directly affected by changes of height of level of the water in the reservoir or ditch 1 andthe consequent changes of inductance of the solenoid 7. Any changes in height of level of the water in the reservoir ,oi' ditch will, however, afiect a corresponding change in the inductance of solenoid 7, and consequently in the ratio of the current through solenoids 13 to the current through solenoids 12 and 21, and hence in the angular position of theplate 15 and .pointer 16. When the rotative effects on plate 15' of the currents through solenoids 12 and 13 are such as to neutralize each other, this plate lies in the plane of solenoids 12 and 13 which is at I right angles to the planes of solenoid 21.

corresponding angular position of the plate will be within the angle formed by theintersection of the plane of solenoids 12, 13 with that of solenoid 21, but on the otherside of the plane of solenoids 12,13. The

angle of rotation of the plate 15, and conterminal of the transverse solenoid which was formerly connected to the inner solenoid 12, is now connected to the branch wire 10. In Fig. 2, the planes of the solenoids inter sect at right angles; in Fig. 3, the planes of the solenoids incline toward each other at an angle less than a right angle. The operation of the instrument with these modifications will be readily understood from the foregoing description. \Vith either of these modifications the angle of rotation of the pointer 16 is governed by the rotary effects upon armature 15, of the current in each of the solenoids 13 and 21, the variations of relative values of these currents depending upon the variations of inductance of the solenoid 7.

By using, instead of solenoid 7 and core 6, a rheostat 40, as shown at Fig. 4, the resistance +11 of which, in series with the wires 8, 9, is made to depend upon the height of level of the water in the reservoir or ditch 1, and by using resistances instead of reactance coils 18, and 25, the indicator may be operated from a source of direct current or of alternating current. In

this case solenoids l2 and 21 may be designed for connection directly between wire 10 and wire 9, resistances in series with these solenoids being eliminated. The rheostat and direct or alternating current may be used in connection with the modifications shown in Figs. 2 and 3.

In the modification, for use with alternating current, shown in Fig. 5, the branch currents flowing through the circuits of which wires 10, 11 are a part, combine and flow through reactance coil 18 to wire 9'. By this arrangement, an increase in the value of the inductance of solenoid 7 (shown in Fig. 1) will cause a decrease in the value of the current flowing through the circuit of which it forms a part directly, and also will cause a greater current to flow through the circuit otwhich wire 10 forms a part directly. In like manner any decrease in the inductance of solenoid 7 will cause an increase of current through wire 11, and a decrease of current through wire 10. The change of the ratio of the currents flowing through the two branch circuits and consequently the relative values of the magnetic forces acting upon the armature 14 are governed by the value ofthe inductance of solenoid 7,- and are independent of such changes in voltage, and freqliency of the operating current as are likely to occur. This modification is for use in connection with the arrangement of solenoids 12, 13 and- 21, as shown in Fig. 1; with the arrangement of solenoids 13, 21, as'shown in Fig. 2; or with the arrangement of solenoids 13, 21, as shown in Fig. 3.

Fig. 6 shows an arrangement similar to that of Fig. 5, for use with either direct increase of current through the circuit of which wire 10 forms a part. In like man ner a decrease of resistance of the rheostat causes an increase of current I flowing through the circuit of which wires 8, 9, form apart, and adecrease of current through the circuit of which wire 10 forms apart. This modification is for use in connection with the arrangement of solenoids shown in Fig. 1, with the arrangement of solenoids 13, 21, as shown in Fig. 2; and.

with the arrangement of solenoids 13, 21, as shown in Fig. 3. Resistance 25 may be eliminated and the wire 22 connected to resistance 18 and wire 9 at their intersection.

In Fig. 1 solenoid 21 and either of solenoids 12, 13, may be connected between wiresll and 26, and the remaining one of solenoids 12, 13, connected between wires 10 and 22, without affecting the accuracy of operation of the instrument. Also sole noid 21 and either of solenoids 12, 13 may be connected between wires 10 and 22, and the remaining one of solenoids. 12, 13 connected between wires 11 and 26, without affecting the accuracy of operation of the instrument. Any suitable means of well known construction may be employed in connection with the pointer 16, shaft 14, and armature 15 for damping the oscillations of the pointer. In general, the branch circuit of which wire 10 forms a part directly may be replaced by two or more circuits without materially affecting the principles involved.

Having thus described the invention what I claim. as new and desire to secureby Letters Patent is 1.In an indicator for electrically designating at a station the height of the levelof I a liquid, supply situated at a dis tanlt point therefrom, ,the combination of a p urality of electric circuits energized from a com mon source of electric energy, one of said' circuits extending to said distant point, with means including a coil situated at such distant polnt for automatically varying the "(M ratio of the current flowing in one of the said electric circuits to the current flowing in each of the remaining circuits in accordance with changes in the height of the level of the liquid at such distant point, electrical connections between saidcoil and the circuit extending to said distant point, a solenoid at the station, and an armature cooperating with said solenoid and acted upon by magnetic forces due to the current flowing through the one and each of the remaining electric circuits for designating th changes of the height of the level of the liquid at a distant point.

2. In an indicator for electrically designating a station the height of level of a liquid supply situated at a distant point therefrom, the combination of two' electric circults energized from a common source of electric energy, one of said circuits extending to said distant point, a variable reactance coil located at said distant point, means including a core operable by the liquid supply at such distant point forchanging the positions relative to each other of the electric circuit and the magnetic circuit of said variable reactance coil for automatically varying the ratio of the current flowing in one of said circuits to the current flowing in theother of the circuits, a solenoid at the station, and an armature coacting with said solenoid and operatable by magnetic forces due to the said currents for designating the height of the ,level of-the liquid at the distant point. f

3. In anvindicator for electfically designating at a station the height of the level of a liquid supply situated at a distant point therefrom, the combination of two electric circuits energized from a common source of electric energy, one'of said circuits extending to said distant point, a variable reactance coil located at said distant point, means including a core operatable by the liquid supply at such distant point for changing the positions relating to each other of the electric circuit and the magnetic circuit of said variable reactance coil for automatically varying the ratio of the current flowing in one of said "circuits to the current flowing in the other circuit in accordance with the variations in the height of level of the liquid, electrical connectionsbetween said core and the circuit extending tov said distant point, a solenoid at the station, and an armature associated with said solenoid acted height of level of the liquid at a distant] point.

4:. In an indicator for electrically designating at a station the height of level of a liquid supply situated at a distant point therefrom, the combination, with a variable reactance coil located at said distant point,

i of means operatable by the liquid supply at such distant point for changing the positions relative to each other of the electric circuit and themagnetic circuit of said coll;

a series electric circuit including said coil energized from a sourceof alternating ourrent and including one of two coaxial solenoids lying in the same plane and a second reactance coil; a second series electric circuit energized from the same source of alternating currentincluding the other of said solenoids, a third reactance coil and a resistance; a-third solenoid, whose plane is atright-angles to the" planes of said other solenoids, connected in series with one of said series circuits; and a pivotally'mounted -armature associated with said solenoids and y 5. In an indicator: for electrically desig- Ii nating at a station the height of level of a liquid supplysituated at a distant point therefrom, the combination with a variable reactancecoilc located at said distant point, p

of means operatable by the liquid supply at such distant point forchanging the positions relative to each other of the electric circuit and the magneticcirc'uit of said coil,

a series electric circuit energized from a source of alternatlng current, lncludmg one of two coaxial solenoids lying in the same plane and including a second reactance coll, a second series electric c1rcu1t energlzed from the same source of alternating current and including the other of said solenoids, said'solenoids being wound in opposlte dlrectlons about their common axis when considered with reference to either N terminal of said source of altermalting cur-' rent, a third reactance coil and esistance included insaid second series circuit, a third solenoid Whose plane is at right-anglesto the planes Tof said other solenoids and which is cdnnected' in series to one of said electric circuits, and an armature pivotally mounted in said'solenoids and adapted to" be acted upon by magnetic forces due to the current flowing in each of said solenoids for I designating the changes "of the height of level of the liquid at said distant'point.

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therefrom, the combination 'of two-electric 6. In an indicator for electrically designating at a station the height of level of a liquid supply situated at a distant point circuits energized from a common source of electrlc energy, one of said rcuitsiextendated at such distant point, for automatically varying the ratio of the current flowing in.

one of said circuits to the current flowing in the other circuit in accordance with changes in the height of level of the liqu d at such distant point, electrical connections between said means and the'circuit extending to said distant point, a solenoid at'the station and an armature associated with such solenoid and directly acted upon by magnetlc forces due to the current flowing through each of the electric circuits for designating the changes in the height of level of the liquid at the distant point.

7. In an electric level indicator, the com-.

bination of two concentric solenoids; an

external clrcult connected to each of said I I o solenolds; means for passing anelectric cur rent through each of said solenoids and its external circuit; means depending upon the height of the level to be indicated for varying the impedance of the external circuit of one' of said solenoids; and a member composedof magnetic substance'freely suspend- I ed in the magnetic field of said solenoids and adapted to be rotated thereby for designating the changes in the height of the level of the liquids at the distant point.

8. 'In an electric level indicator, the combination of two adjacent solenoids; an external circuit connected to each of said solenoids; means for conducting from a common source an M alternating electric current through each of. said solenoids and its external circuit; means depending upon the height of the level to be indicated for varying the reactance of the external circuit of one of said solenoids; and a magnetic member,freely suspended in the commonmagnetic field of said solenoids for designating the changes in the height of the level of the liquids atthe distant point.

9. In an elect '0 level indicator, the com bination 'of two concentric solenoids; an ex-. ternal circuit connectedto each of said solenoids; means for conducting from a common source an electric current through each of said solenoids and its external circuit; means depending upon the height of the level to be indicated for varying the impedance of one of the external circuits; ad-' justable resistance in one of said external circuits; and a magnetic member rotatably suspended in the common magnetic field of said solenoids and adapted to be rotated thereby for designating thechanges in the height of the level of the liquids at the distant point.

101 In an electric level indicator, the combmation of two adjacent. sol'enoids; an external circuit connected to each of'said solenoids; means for conducting from a common source an alternating current through D each' ofnsaidi solenoids and its external cir- 1ng to said distant point, with means situcuit; aheansdepending upon the, heightof the levelto be indicated for varying the re-. actance of the external circuit of one of said solenoids; an adjustable resistance in one of said. external circuits; and a rotatable afimafi Suspended. in 6 mmon of the substance to be indicated for varying the impedance of one of the external circuits; and an armature rotatably suspended in the common magnetic field of said solenoids and adapted to be rotated thereby for designating the changes in the height of the Y level of the liquid at the distant point.

12. In an, electric level indicator, the combination of two adjacent coils, [and electric circuits therefor; means for conducting an alternating electric current through each of said coils and its circuit means controlled by the variations in height ofthe level of the substance to be indicated for varying the reactance of the circuit of one of said coils; and a magnetic member of low retentiveness rotatably suspended in the common magnetic field of said coils for designating the changes in the height of the level of the liquid at the distant point. I I

13. In an electric level indicator, the combination of two adjacent coils and electric circuits therefor; means for conducting from a common source an alternating electric current through each of said coils and its circuit; means'controlled by the variations in the height of the level of the substance to be indicated for varying the phase'relation of the current to its pressure in one of the circuits; and indicating means associated with said coils controlled bythevaryin'g phase relations between said currents for designating the changes in the height of the level of the liquid at the distant point. L

14. In an electric level indicator, the combination of two concentric solenoids, and electric circuits therefor; means for conducting an electric current through each of said solenoids and its circuit; means depending upon the height of the level to be indicated for varying the impedance of one of the circuits; adjustable resistance in one of said circuits; and a magnetic member rotatably suspended in "the common magnetic field of said solenoids and adapted to be rotated thereby.

15. In an electric level indicator, the combination of two concentric solenoids, and

said solenoids; means for conducting by for conducting'from a common source an alternating electric current through each of said solenoids and its circuit; means controlled by the variations in the height of the level of the substance to be indicated for varying the phase relations of said currents; a magnetic member of low retentiveness rotatably sus pended in the common magnetic solenoids and adapted to be rotatably afl'ected thereby; one'of said circuits. e

16. In an electric indicating apparatus, the combination of two adjacent solenoids and external circuits therefor; means for conducting from a commonsource of electric and an adjustable resistance in field of said current through each'of said solenoids sea its circuit; means controlled byvthe variations which are to be indicated for varying the relation of the ohmic resistance to the reactance of the circuit to one of said solenoids;"and adjustable resistance inthe other circuit; and an armature suspended in the common magnetic field of said solenoids and adopted to be rotated thereby.

17; In an electric level indicator, the combination of two concentric and coaxial solenoids and electric circuits therefor; means for conducting an electric current through each of said solenoids and its circuit; means operated by the variations inheight of the level of the substance to be indicated for varying the impedance of one of the circuits; an armature suspended in the common magnetic field of said solenoids and adapted to be rotated thereby; "an indicating arm rigidly connected with said armature; and anadjustable resistance in one of'said circuits.

18. In an electric level indicator for-designating at a station the height of level of a liquid supply situated at a distant point, the

combination of two electric circuits, one extending to said distant point, means for conducting from a common source an=alternatcults, a coil in said'circuit leading to said distant point, a magnetic member cooperating with said coil; means depending upon the height of the level to be indicated for changing. the position of said member with reference to said coil, and means for ind cating variations in the reactance of said circuits.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses; 1

' GEORGE E. HENDERSON.

Witnesses: I e e D. B. RIoHARns, HARRY Gr. To'rmn. 

